/*
 * Copyright (C) 2006 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package android.os;

/**
 * WARNING: This class overrides one in the private android system. Its here to
 * allow things to compile and depends on Java's classpath loading mechanism to
 * load the real one from the system.<br/>
 * 
 * Gives access to the system properties store. The system properties store
 * contains a list of string key-value pairs.
 * 
 */
public class SystemProperties {
	public static final int PROP_NAME_MAX = 31;
	public static final int PROP_VALUE_MAX = 91;

	private static native String native_get(String key);

	private static native String native_get(String key, String def);

	private static native int native_get_int(String key, int def);

	private static native long native_get_long(String key, long def);

	private static native boolean native_get_boolean(String key, boolean def);

	private static native void native_set(String key, String def);

	/**
	 * Get the value for the given key.
	 * 
	 * @return an empty string if the key isn't found
	 * @throws IllegalArgumentException
	 *             if the key exceeds 32 characters
	 */
	public static String get(String key) {
		if (key.length() > PROP_NAME_MAX) {
			throw new IllegalArgumentException("key.length > " + PROP_NAME_MAX);
		}
		return native_get(key);
	}

	/**
	 * Get the value for the given key.
	 * 
	 * @return if the key isn't found, return def if it isn't null, or an empty
	 *         string otherwise
	 * @throws IllegalArgumentException
	 *             if the key exceeds 32 characters
	 */
	public static String get(String key, String def) {
		if (key.length() > PROP_NAME_MAX) {
			throw new IllegalArgumentException("key.length > " + PROP_NAME_MAX);
		}
		return native_get(key, def);
	}

	/**
	 * Get the value for the given key, and return as an integer.
	 * 
	 * @param key
	 *            the key to lookup
	 * @param def
	 *            a default value to return
	 * @return the key parsed as an integer, or def if the key isn't found or
	 *         cannot be parsed
	 * @throws IllegalArgumentException
	 *             if the key exceeds 32 characters
	 */
	public static int getInt(String key, int def) {
		if (key.length() > PROP_NAME_MAX) {
			throw new IllegalArgumentException("key.length > " + PROP_NAME_MAX);
		}
		return native_get_int(key, def);
	}

	/**
	 * Get the value for the given key, and return as a long.
	 * 
	 * @param key
	 *            the key to lookup
	 * @param def
	 *            a default value to return
	 * @return the key parsed as a long, or def if the key isn't found or cannot
	 *         be parsed
	 * @throws IllegalArgumentException
	 *             if the key exceeds 32 characters
	 */
	public static long getLong(String key, long def) {
		if (key.length() > PROP_NAME_MAX) {
			throw new IllegalArgumentException("key.length > " + PROP_NAME_MAX);
		}
		return native_get_long(key, def);
	}

	/**
	 * Get the value for the given key, returned as a boolean. Values 'n', 'no',
	 * '0', 'false' or 'off' are considered false. Values 'y', 'yes', '1',
	 * 'true' or 'on' are considered true. (case insensitive). If the key does
	 * not exist, or has any other value, then the default result is returned.
	 * 
	 * @param key
	 *            the key to lookup
	 * @param def
	 *            a default value to return
	 * @return the key parsed as a boolean, or def if the key isn't found or is
	 *         not able to be parsed as a boolean.
	 * @throws IllegalArgumentException
	 *             if the key exceeds 32 characters
	 */
	public static boolean getBoolean(String key, boolean def) {
		if (key.length() > PROP_NAME_MAX) {
			throw new IllegalArgumentException("key.length > " + PROP_NAME_MAX);
		}
		return native_get_boolean(key, def);
	}

	/**
	 * Set the value for the given key.
	 * 
	 * @throws IllegalArgumentException
	 *             if the key exceeds 32 characters
	 * @throws IllegalArgumentException
	 *             if the value exceeds 92 characters
	 */
	public static void set(String key, String val) {
		if (key.length() > PROP_NAME_MAX) {
			throw new IllegalArgumentException("key.length > " + PROP_NAME_MAX);
		}
		if (val != null && val.length() > PROP_VALUE_MAX) {
			throw new IllegalArgumentException("val.length > " + PROP_VALUE_MAX);
		}
		native_set(key, val);
	}
}
